OFFSET
1,2
EXAMPLE
a(3) = 6 because 6 is the smallest number with the property that exactly three of its divisors are partition numbers. The divisors of 6 are 1, 2, 3, 6, and 1, 2, 3 are also partition numbers.
a(5) = 42 because 42 is the smallest number with the property that exactly five of its divisors are partition numbers. The divisors of 42 are 1, 2, 3, 6, 7, 14, 21, 42, and 1, 2, 3, 7, 42 are members of A000041.
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
Omar E. Pol, Jan 22 2014
EXTENSIONS
a(12) and a(15)-a(18) from Alois P. Heinz, Jan 22 2014
a(19)-a(22) from Giovanni Resta, Feb 06 2014
a(23) from Amiram Eldar, Jun 23 2023
STATUS
approved